I'm pretty sure that as of today LLNL isn't shut down. Unlike, say, NASA's Goddard Space Flight Centre, the people who work there are government contractors and the lab is run by a third party corporation for the US Government. This is much the same as Los Alamos (still running) and JPL.

Of course, their money will soon run out, at which point they will have to shut down, but I think the author (of the CBS news item) may be reaching here linking the lack of publicity about this finding (even though I did read about it myself a few days ago), with the Government shutdown.

Considering, these lasers have a 90% energy lost that's just 10% of overall energy investment, hardly "break-even". The Joint European Torus (JET) achieved 70% in 1997, and with the new ITER to be available in 2019 it's more likely to get 100% right from the start. But you need something in the 1000% to have a real powerplant.

Considering, these lasers have a 90% energy lost that's just 10% of overall energy investment, hardly "break-even". The Joint European Torus (JET) achieved 70% in 1997, and with the new ITER to be available in 2019 it's more likely to get 100% right from the start. But you need something in the 1000% to have a real powerplant.

Well, obviously. It's right in the article that the lasers delivered 1.8MJ, and fusion produced 8kJ (though I've seen other reports that say 14kJ). And this doesn't even take into account the energy delivered to the lasers, and their efficiencies, or the other power consumption in the process (vacuum pumps, cryogenic refrigeration units, etc...)

What happened is that the fusion plasma was actually significantly heated by the reaction alphas. This is the first step to getting 'ignition' where the dominant heat in the plasma is from the alphas. However, getting to a power plant means turning up the yield significantly (~4 orders of magnitude), and increasing the rep rate from 1 every day or so to 5-10 per second, and clearing out the debris from the explosion in between.

Not an easy task.

You should note though that the 70% JET results were also not taking into account system power consumption.

Considering, these lasers have a 90% energy lost that's just 10% of overall energy investment, hardly "break-even". The Joint European Torus (JET) achieved 70% in 1997, and with the new ITER to be available in 2019 it's more likely to get 100% right from the start. But you need something in the 1000% to have a real powerplant.

Well, obviously. It's right in the article that the lasers delivered 1.8MJ, and fusion produced 8kJ (though I've seen other reports that say 14kJ). And this doesn't even take into account the energy delivered to the lasers, and their efficiencies, or the other power consumption in the process (vacuum pumps, cryogenic refrigeration units, etc...)

What happened is that the fusion plasma was actually significantly heated by the reaction alphas. This is the first step to getting 'ignition' where the dominant heat in the plasma is from the alphas. However, getting to a power plant means turning up the yield significantly (~4 orders of magnitude), and increasing the rep rate from 1 every day or so to 5-10 per second, and clearing out the debris from the explosion in between.

Not an easy task.

You should note though that the 70% JET results were also not taking into account system power consumption.

The article uses inaccurate terminology. This isn't Kate's fault, the same errors crop up in all the stories on the subject.

'Ignition' is a bit ill-defined but basically you have some level of ignition if you get fusion. In a laser type system there is no self-sustaining reaction, the fuel in the 'pellet' fuses to some degree and then the pellet disintegrates, at which point fusion ceases.

'break even' is where you would get out more energy than was required to initiate fusion. Obviously this is not even close.

The article makes it sound like 'ignition' is a point where the system is self-sustaining, but that would REALLY only be possible at or beyond break-even. In this case they do seem to be using 'ignition' to mean that enough thermal energy was retained in the pellet at high enough plasma densities for a long enough time that some significant fusion took place and that the thermal energy released by that fusion contributed at some stage in the process to MORE fusion, not a necessary condition for success, but probably one that any successful system would achieve. Its a bit confusing.

Anyway, its an interesting experiment. I tend to think it is worth less hype than it is getting, but still, it is pretty interesting.

Remember that between fission being discovered by Hahn and Strassman in late 1938 and the Italian navigator landing in the new world, i.e. Fermi running the world's first controlled nuclear fission reactor were only 4 years. The first nuclear power station began feeding the grid in 1954, a mere 12 years after that. All in all, that's less than 20 years.

I'm pretty sure that as of today LLNL isn't shut down. Unlike, say, NASA's Goddard Space Flight Centre, the people who work there are government contractors and the lab is run by a third party corporation for the US Government. This is much the same as Los Alamos (still running) and JPL.

Just wondering, do you work at Goddard? That's a fairly specific choice for an example otherwise. Note: there are certainly contractors that work at Goddard (in fact that's about 75-80% of the workforce).

The fusion part appears to be enough energy to run a coffee maker for like 10 seconds or the energy content of 2 grams of sugar. Like ethanol the issue what the energy costs are for the setup and clean up. The lasers delivering 1.8 MJ to get 8kJ matters because the lasers are really inefficient usually. The Wiki says that the capacitors for the laser store 422 MJ so the lasers only have a conversion efficiency of like .5% to get the 1.8 MJ so ignoring all the energy cost for target prep and clean up and the cost of conversion of the heat to something more usable this path need to improve by ~ 53000 times.

As a layman, the fact that the reaction generated more energy than the fuel actually absorbed seems like it should be significant. Is that correct? Is this an important threshold? I mean, without being able to get more out of the reaction than you put in, even a perfectly efficient fusion reactor would lose energy on every ignition, so in that sense it's obviously important, but I can't figure if there's any fundamental difference between an exothermic fusion reaction and an endothermic one.

I'm pretty sure that as of today LLNL isn't shut down. Unlike, say, NASA's Goddard Space Flight Centre, the people who work there are government contractors and the lab is run by a third party corporation for the US Government. This is much the same as Los Alamos (still running) and JPL.

Of course, their money will soon run out, at which point they will have to shut down, but I think the author (of the CBS news item) may be reaching here linking the lack of publicity about this finding (even though I did read about it myself a few days ago), with the Government shutdown.

True, these labs are currently running on overhead, but once that's out they will be furloughed. I know this because a good friend of mine is a post doctoral researcher at Argonne and she's freaking out about being furloughed 'soon.' (but no specific date has been given)

Maybe we could just throw Congress into the reaction chamber? Maybe all that hot air would be that extra push we need to achieve ignition.

I love the fact that this has ~50 upvotes and zero downvotes. Whoever said liberals and conservatives couldn't agree on anything?

I think the current 28% approval rating of the congress proves that all people who can both walk and chew gum at the same time think that we need to ditch them all and vote in our respective domestic pets.

Considering, these lasers have a 90% energy lost that's just 10% of overall energy investment, hardly "break-even". The Joint European Torus (JET) achieved 70% in 1997, and with the new ITER to be available in 2019 it's more likely to get 100% right from the start. But you need something in the 1000% to have a real powerplant.

I think the current 28% approval rating of the congress proves that all people who can both walk and chew gum at the same time think that we need to ditch them all and vote in our respective domestic pets.

That pretty high I have seen polling as low as 8% Did you know people have a higher opinion of zombies than congress, according to some polling?

[quote=[url=http://arstechnica.com/civis/viewtopic.php?p=25463549#p25463549]I think the current 28% approval rating of the congress proves that all people who can both walk and chew gum at the same time think that we need to ditch them all and vote in our respective domestic pets.

That pretty high I have seen polling as low as 8% Did you know people have a higher opinion of zombies than congress, according to some polling?

I fully blame Washington for this mess. But, at the same time, it seems some of the federal agencies are going out of their way to be more than a bit dramatic.If reports are true that people are getting thrown out of homes they own within national parks, it's ridiculous. Even if those are vacation homes, there seems little valid reason to tell people to leave beyond spite.

As a layman, the fact that the reaction generated more energy than the fuel actually absorbed seems like it should be significant. Is that correct? Is this an important threshold? I mean, without being able to get more out of the reaction than you put in, even a perfectly efficient fusion reactor would lose energy on every ignition, so in that sense it's obviously important, but I can't figure if there's any fundamental difference between an exothermic fusion reaction and an endothermic one.

The type of fusion reaction they are going for is always exothermic (fusing into anything heavier than iron is endothermic and thus pointless for energy production -- trying is what ends up killing massive stars).

What they did here is cause enough of the reactant to fuse that it output more energy than they put into those reactants. And apparently part of how that happened is that the energy from the fusion they initiated caused more fusion, which is certainly a feature.

This is indeed an important step.

But it's a long way from a functioning reactor because looking only at the energy in/out of the reactants is very different from energy in/out of the entire system. As already pointed out energy into the reactants is a small fraction of energy measured "at the plug" as it were. And then they still need to turn energy out into useful energy out.